SoliForum - 3D Printing Community — better heated bed for SD4?

Re: better heated bed for SD4?

2015-02-09T22:15:47Z

Yup - Glass+Hairspray. Glue stick works, too, but I find hairspray is more consistent and easier. The moment of nirvana came for me when I discovered the "First Layer" modifier to the extrusion width in the advanced settings. 150% is about perfect. For large prints that will tend to lift at the corners, I go to 200% and add a brim but that often pulls chips out of the glass with the part when I remove it. At settings over 100%, this makes slicer print wider tracks for the first layer which really helps it get a grip.

Re: better heated bed for SD4?

2015-02-09T19:55:20Z

Glass and Hairspray all day long...If I think a print will give me trouble, I might use brim and glue stick the edges, but that's rare.

Height was about 1.5" with 40% infill; 3 perimeters.

Re: better heated bed for SD4?

2015-02-09T19:29:40Z

I just want some info on PCB beds from people who use it.
All I care is not getting warping on the edges. If I won't, then I don't care if the edge is same temp as the middle or different.
I already bought PCB beds and silicone bed isn't cheap. Not to mention i can't find any with 3 holes for a Solidoodle 8'' bed. Is there any?

8.5 for 10'' bed with no warping sounds good. What did you use? Glass and hairspray/glue stick?
What was the height and infill of the object? I've heard the denser and bigger the print, the more likely it is to warp.

I would like to hear pirvan's experience as well, he said the silicone mats were the ones not providing even heat distribution for him instead.

Re: better heated bed for SD4?

2015-02-09T17:04:53Z

My bed is 10" x 10"...since I'm still using binder clips I avoid 1/2" along the edges. Longest print span I ever did along one axis was about 8.5" with no lifting...except when I tried using the BuildTak surface! IMHO it is not good for ABS!

Again, your call on the silicone pad. For me, the PCB works, but if you want better consistency on the surface, then go for the silicone...at the end of the day, you need to be happy with your mods!!

Re: better heated bed for SD4?

2015-02-09T16:27:45Z

It's not a concern as long as my prints don't warp.
So as long as middle of bed being 10C higher doesn't cause warping as long as the edges of the bed are still above a certain temp, then I don't have a problem.
If, however, warping will happen at any temp if there's a temperature variations on the bed, then yeah, that's an issue.

That's the reason I wanted to replace the stock heater as I mentioned in my first post.

redbarret wrote:

Okay, so I'm unable to get anything to stick closer to the edges of my bed. I've tried both kapton tape and glass+ hairspray. If glue sticks dont work either, Im going to conclude the heated bed of SD4 cant provide even distribution of heat and switch th a PCB bed.

What's the largest object you've printed so far IronMan?

Re: better heated bed for SD4?

2015-02-09T15:11:06Z

Agreed that most PCB beds will have that heat variation to the edges...but if you run it at 110C for ABS, the variation at the edges is still fine for good adhesion...

If this is still a concern, then the silicone heat pad could be a better choice for you...

Re: better heated bed for SD4?

2015-02-08T20:40:26Z

So I have to come back to this thread again.
Many people here suggested me to go with PCB beds instead of larger heater pads.
But I recently looked up some ir images of heated bed comparisons, and MK2B heatbed shows 10-15C difference between the center of the bed compared to closer to the edges.
While an aluminum with appropriately sized heater mat below provides more uniform heating.

So I have a question to those who suggested me and anyone else who would suggest the PCB beds...
Do you guys print anything large? Where the edges of your model reach the edges of the print bed? Does that 10-15C deviation in temp cause warping for you guys?

My PCB bed hasn't shipped yet and I'm seriously considering not using them now and going with 8''x8'' silicone heater mat instead, if the temperature deviation would be an issue with warping, which is the sole reason I want to switch the stock 6''x6'' mat with a larger heater in the first place...

Re: better heated bed for SD4?

2015-01-03T22:30:34Z

redbarret wrote:

jagowilson, where have you found PCB beds with 3 holes instead of 4?
BTW, can someone explain how connecting a silicone pad to the motherboard bed heater pins directly can damage the motherboard like the eBay seller said? I would only think of it not heating or not heating properly. Not that I'm going to get a silicone pad, but just curious.

It's not necessarily the silicon pad that damages, it's the fact that most (?) silicon pads are higher wattage than 'stock' bed heaters. Since watts are volts multiplied by amps, for a fixed voltage (like with a 12V power supply) a higher wattage load (heater) will require (and 'take', or draw) more current. The FET/TRansistor/Wiring/Etc on the controller board can only handle so much current. Too much current asked from it will cause it to over-heat and something will burn out.

Kind of like when you see in comics someone plugging in too many things into one household outlet (with adapters, power strips, etc) all these things draw extra watts, or extra current, and when it adds up to more than the outlet can handle, things get hot, something melts, hand something shorts out....

- Steve

Re: better heated bed for SD4?

2014-12-19T00:13:24Z

Yup! More info if you're interested:

* Higher amp rating = cooler running. Note that the full rating is specified assuming a pretty serious heatsink.
* As ironman can attest, failure can be fail-on, which is potentially a fire hazard, so it's worth investing in headroom. The SSR isolates the motherboard from the heatbed current, so a massive SSR failure will usually not damage the motherboard - this is an advantage of a relay in general.
* Mechanical relays also fail-on in high current applications (contacts spark, resistance goes up, heat generated increases, finally enough to weld), so really you don't lose anything by picking an SSR.
* The SSR can switch on and off quite quickly, and has a near infinite cycle life, so is compatible with PWM control of the bed (a mechanical relay will buzz and not last very long!!). Note that it may run hotter in PWM mode than bang-bang, as heat is generated in the transition as it switches. I'm not actually sure what kind of frequency the bed PWM runs at, I think it's quite low so you might not notice this...

Re: better heated bed for SD4?

2014-12-18T19:55:25Z

The larger amperage should keep it cooler, not working at max lvl. Also the board will draw what it needs. 10 to 14 amps depending on the heat bed replacement you decide on getting. You want a solid state relay as you do not want it getting stuck on as it could cause a fire.

Hey redbarret here's another http://www.ebay.com/itm/30-Amp-Relay-Bo … 4d1ce63f9b

According to their page they ship world wide, same thing as the other, just different set up.

Re: better heated bed for SD4?

2014-12-18T14:17:38Z

My SD2 is stock with a glass bed; the 10" x 10" is my self-built Ord Bot Hadron...

Re: better heated bed for SD4?

2014-12-18T14:06:57Z

Thanks for the info. So I guess a SSR can have serious consequences on the motherboard, but it depends on each case?

BTW, this is off topic, but you have a Solidoodle 2 but a 10''x10'' heated bed? Any reason for that?

Re: better heated bed for SD4?

2014-12-18T13:49:53Z

redbarret wrote:

How much A is your heated bed?
BTW, what happened when you fried your SSR? The heater just stopped working? or some damage was done to the mobo?

The bed draws 18-20A during warmup...then draws about 16A to keep temp. Bear in mind my PCB is 10" x 10"

When the SSR failed, it just heated up so much that it fried the MOSFET within and melted the outer casing. It also failed in the ON condition which would have been pretty serious if I had not been supervising.

Nothing happened to the Motherboard.

Re: better heated bed for SD4?

2014-12-18T12:51:53Z

How much A is your heated bed?

BTW, what happened when you fried your SSR? The heater just stopped working? or some damage was done to the mobo?

Re: better heated bed for SD4?

2014-12-18T12:02:53Z

redbarret wrote:

Thanks again. So no harm from more Amperage rating?
lets say I only find 20 or 30A, how will I know it still isn't enough? Heat generated? Or is some heat generated normal?

With regard to the SSR, I fried a 30A rated version when my PCB heater was rated for 20A...so I ended up with a 60A SSR...it still gets warm, but with a heat sink and cooling fan it works great.

Really just trial and error...